A piece for building a toy, having a protrusion on one side and an insertion hole in the other side are in wide use to foster children's creativity. Children can play creatively while building a toy by inserting the protrusion on the one side of one piece into the insertion hole in the other side of the other piece.
A new-type of piece with magnets for building a toy is growing in popularity, which connects to the other piece with magnets to build a toy.
The piece 10, as shown in FIG. 1, has two magnets 16 on ends, one on each end. The magnet 16, provided fixedly on each end of the piece 10 has its south pole face toward outside and the magnet 16 on the other end of the piece 10 has its north pole face toward outside. The two pieces 10, which are the same in construction, connects to each other with a magnetic ball 12 to build a variety of toys. However, contact surfaces 35 of the two pieces 10, when having like poles, cannot connect to each other without the magnetic ball 12. It's because like poles repel and unlike poles attract. So, any one of the two pieces 10 has to turn 180 degrees.
A conventional technology of solving this problem is described in Korean Patent No. 545658. In the conventional technology, a piece 10 for building a toy has a space 20 inside, where a magnet 16 is placed. The magnets 16 are freely movable or rotatable in the spaces 20 when the like poles are opposite to each other. Thus, when unlike poles are opposite to each other, the two pieces 10 connect with each other by magnetic forces.
However, the space 20 should be large enough for the magnet 16 to be freely movable or rotatable in it. This makes it difficult for the piece 10 to be small-sized. The small-sized piece 10 requires the corresponding small-sized space 20, which in return requires the use of the small-sized magnet 16. When the small-sized magnet is placed in the space 20, the magnet force is smaller. Furthermore, when two toys are independently built connecting the pieces, they can connect to each other later. Two or more magnets have to be placed in the space 20 to connect the independently-built toys. This requires the larger-sized space 20, thereby making it difficult for the piece to be small-sized. Children cannot easily distinguish between the piece which has two or more magnets in it, and the piece which has one magnet in it.
Another conventional technology of connecting the pieces without having to use the magnetic ball is disclosed in Korean Utility Model Registration No. 404030. The piece 10, as shown in FIG. 3, has a circular magnet 16, of which one face has both north and south poles, on the contact surface 35. The circular magnet 16 is rotatable along the inside circumferential surface 11 of the body. However, this causes friction between the outside circumferential surface of the magnet 16 and the inside circumferential surface 11 of the body, thereby preventing smooth rotation of the magnet 16. Furthermore, the magnet 16 whose one face has both north and south poles is expensive, thereby increasing a cost for manufacturing the piece 10 with this construction.